From seth@psychotic.aberrant.org  Tue May 15 07:01:15 2001
Return-Path: <seth@psychotic.aberrant.org>
Received: from psychotic.aberrant.org (psychotic.aberrant.org [64.81.134.141])
	by hub.freebsd.org (Postfix) with ESMTP id 8F9A337B440
	for <FreeBSD-gnats-submit@freebsd.org>; Tue, 15 May 2001 07:01:14 -0700 (PDT)
	(envelope-from seth@psychotic.aberrant.org)
Received: by psychotic.aberrant.org (Postfix, from userid 1000)
	id D071672501; Tue, 15 May 2001 10:01:13 -0400 (EDT)
Message-Id: <20010515140113.D071672501@psychotic.aberrant.org>
Date: Tue, 15 May 2001 10:01:13 -0400 (EDT)
From: seth@psychotic.aberrant.org
Reply-To: seth@psychotic.aberrant.org
To: FreeBSD-gnats-submit@freebsd.org
Cc:
Subject: load average constantly above 1.0, even when idle
X-Send-Pr-Version: 3.113
X-GNATS-Notify:

>Number:         27334
>Category:       kern
>Synopsis:       load average constantly above 1.0, even when idle
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue May 15 07:10:02 PDT 2001
>Closed-Date:    Wed Nov 14 17:05:13 PST 2001
>Last-Modified:  Wed Nov 14 17:17:45 PST 2001
>Originator:     Seth
>Release:        FreeBSD 4.3-STABLE i386
>Organization:
>Environment:
System: FreeBSD psychotic.aberrant.org 4.3-STABLE FreeBSD 4.3-STABLE #0: Mon May 14 22:11:40 EDT 2001 seth@psychotic.aberrant.org:/usr/src/sys/compile/KERNEL-E i386

-STABLE from two days ago (13 May 2001).

AMD Athlon Thunderbird 1GHz, /proc filesystem, securelevel=1.


>Description:
This sounds similar to kern/21155, but occurs in -STABLE rather than
-CURRENT.  It didn't happen on my old system (a dual-proc ppro 200), but
there are so many differences: smp, 4.0 (vs -stable) that it's not a good
comparison.

Nothing seems to be affected, but any programs that rely on load average to
determine whether or not to take or suspend action will be affected.  This
is why I made this report a medium priority.

A quick snapshot from top:

last pid:  1729;  load averages:  1.00,  1.00,  1.00    up 0+11:41:00  09:58:15
40 processes:  1 running, 39 sleeping
CPU states:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
Mem: 12M Active, 39M Inact, 21M Wired, 60K Cache, 35M Buf, 177M Free
Swap: 512M Total, 512M Free

  PID USERNAME PRI NICE  SIZE    RES STATE    TIME   WCPU    CPU COMMAND
 1729 seth      28   0  1892K  1172K RUN      0:00  1.08%  0.20% top
 1367 root       2   0  2272K  1892K select   0:01  0.00%  0.00% sshd
 1348 root       2   0  2232K  1852K select   0:01  0.00%  0.00% sshd
  158 root       2 -12  1256K   844K select   0:00  0.00%  0.00% ntpd
 1356 seth       2   0  2152K  1876K select   0:00  0.00%  0.00% epic-EPIC4-1.0
 1354 seth       2   0  1568K  1256K select   0:00  0.00%  0.00% screen


(there's more, but those are the top 6.)


>How-To-Repeat:
  run top or uptime, check load average.

>Fix:

	
>Release-Note:
>Audit-Trail:

From: Ian Dowse <iedowse@maths.tcd.ie>
To: seth@psychotic.aberrant.org
Cc: FreeBSD-gnats-submit@freebsd.org, iedowse@maths.tcd.ie
Subject: Re: kern/27334: load average constantly above 1.0, even when idle 
Date: Tue, 15 May 2001 16:40:23 +0100

 In message <20010515140113.D071672501@psychotic.aberrant.org>, seth@psychotic.a
 berrant.org writes:
 >
 >This sounds similar to kern/21155, but occurs in -STABLE rather than
 >-CURRENT.  It didn't happen on my old system (a dual-proc ppro 200), but
 >there are so many differences: smp, 4.0 (vs -stable) that it's not a good
 >comparison.
 
 Hi, could you try downloading
 
 	http://www.maths.tcd.ie/~iedowse/FreeBSD/loadps.tgz
 
 and extracting the tarfile somewhere (/tmp or whatever). Then in the
 "loadps" directory, type:
 
 	make
 	./loadps axlww
 
 This should show up all processes that are currently contributing to
 the load average. That should at least begin to narrow down what
 is causing these phantom load effects.
 
 (loadps is a normal -STABLE ps with a small adjustment that causes it
 see only processes that are contributing to the load average - this
 logic is copied from loadav() in sys/vm/vm_meter.c).
 
 Ian

From: Seth <seth@psychotic.aberrant.org>
To: Ian Dowse <iedowse@maths.tcd.ie>
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: kern/27334: load average constantly above 1.0, even when idle
Date: Tue, 15 May 2001 11:42:53 -0400

 Ian,
 
 Thanks.  Here's the output:
 
 psychotic 514: ./loadps axlww; uptime
   UID   PID  PPID CPU PRI NI   VSZ  RSS WCHAN  STAT  TT       TIME COMMAND
     0     0     0   0 -18  0     0    0 sched  DLs   ??    0:00.00  (swapper)
     0     4     0   0 -18  0     0    0 psleep DL    ??    0:00.08  (bufdaemon)
  1000  1994  1725   1  28  0  1084  616 -      R+    p3    0:00.00 ./loadps axlww
 11:42AM  up 13:24, 4 users, load averages: 1.06, 1.03, 1.01
 
 
 Seth.
 
 On Tue, May 15, 2001 at 04:40:23PM +0100, Ian Dowse wrote:
 > In message <20010515140113.D071672501@psychotic.aberrant.org>, seth@psychotic.a
 > berrant.org writes:
 > >
 > >This sounds similar to kern/21155, but occurs in -STABLE rather than
 > >-CURRENT.  It didn't happen on my old system (a dual-proc ppro 200), but
 > >there are so many differences: smp, 4.0 (vs -stable) that it's not a good
 > >comparison.
 > 
 > Hi, could you try downloading
 > 
 > 	http://www.maths.tcd.ie/~iedowse/FreeBSD/loadps.tgz
 > 
 > and extracting the tarfile somewhere (/tmp or whatever). Then in the
 > "loadps" directory, type:
 > 
 > 	make
 > 	./loadps axlww
 > 
 > This should show up all processes that are currently contributing to
 > the load average. That should at least begin to narrow down what
 > is causing these phantom load effects.
 > 
 > (loadps is a normal -STABLE ps with a small adjustment that causes it
 > see only processes that are contributing to the load average - this
 > logic is copied from loadav() in sys/vm/vm_meter.c).
 > 
 > Ian
State-Changed-From-To: open->closed 
State-Changed-By: iedowse 
State-Changed-When: Wed Nov 14 17:05:13 PST 2001 
State-Changed-Why:  

This is believed to be caused by synchronisation between some system 
processes and the samples that are used to compute the load avarage. 
Revision 1.87.2.4 of kern_synch.c and assiciated changes should  
fix this; please let us know if the problem continues to occur so 
that the PR can be re-opened if necessary. 

http://www.FreeBSD.org/cgi/query-pr.cgi?pr=27334 
>Unformatted:
